Process for segregating hydrocarbons



June 16, 1942. QCQN PROCESS FOR SEGREGATING HYDROCARBONS Filed June 29,1938 2 Sheets-Sheet l a a 3 P 0 u 2 HE J 1 8 m2: .I l LR m J ms mw a a n7 c a O cm Ill! 8 H 4 a L .1

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Patented June 16, 1942 UNITED STATES PATENT OFFICE PROCESS FOR SI ICZZZZATING HYDRO Ernest A. Ocon, Yonkers, N. Y.

Application June 29, 1938, Serial No. 216,629

8 Claims.

This invention relates to a means and method for segregating from amixture of various miscible hydrocarbons a liquid concentrate of method.While distillation is sometimes effective when carried out withprecision, it is thus uneconomical when used on a large scale; hence,was tried the separation by liquid solvents calculated to have selectivechemical afiinities for certain components with an expectation thattwodistinct phases of liquid would separate by the action of gravity onaccount of the. difference in density between an undissolved componentphase and a dissolved component phase.

The latter method of separation has been found impractical for intensiveisolation of specific components.

I have found that simple distillation using the ordinary kinds of vaporfractionation devices, such as bubble towers and gravitationalseparation means, even those in which mechanical centrifuging means areused for amplifying the force of gravity, are "very inefficient inovercoming the powerful intermolecular forces of attraction be tween thehydrocarbon components, between the solute and undissolved components,and even those between the solvent and solution for the undissolvedcomponents. I have, therefore, devised a method of separation whichemploys forces having magnitudes closer to those of the intermolecularforces and operates on matter maintained principally in a dispersedcondition so as to weaken the intermolecular attraction between thehydrocarbon components. A very simple illustration of the manner inwhich my method operates can be observed in the well known distillationtest for determining the quantity of water in gasoline. In this testalmosta negligible quantity of water which is homogeneously dissolved inthe gasoline can be segregated in a gaseous atmosphere.

water molecules coalesce and condense out from the remaining hydrocarbonvapors.

An object of this invention is to obtain dispersion of mixedhydrocarbons and volatility controlling agent and to induce thepropercoalescence of specific hydrocarbon components with an apparatusdesigned to carry out these manipulations effectively and with economyof energy, since the known kinds of vapor fractionating equipment arenot satisfactorily adapted.

for the use of my method, and neither are the known types of centrifugeswhich depend for operation solely upon rapidly rotating parts. Furtherobjects reside in the application of my method. These and other objectswill become apparent from the following description and the claims.

As can be readily noted,- this invention has applications of a greatvariety, for example, in isolating substantially pure individualhydrocarbons from a very close cut of hydrocarbons, such as refinerygas, gasoline, etc., for fractionating emulsions which easily foam inordinary distillation, for absorbing natural gas, for dehydrating ahydrocarbon oil, for incorporating 'anti-detonating agents into fuelsefficiently, for

segregatinganti-knock components from motor fuels, for segregatingnon-paraffinoid hydrocarbons from lubricating oils, and forfractionation of any type of mixture or solution largely com usually isa substance normally in liquid state, partly immiscible with thehydrocarbon mixture,

having somewhat greater polarity (solubility in water) than thehydrocarbons, selectively greater chemical attraction for the type ofhydrocarbons intended to be segregated as a liquid concentrate, andlower-volatility than the hydrocarbons to be left in the vapor state. Bydispersing is meant conversion of a substance into gaseous or vaporstate, into thin films on a solid contact surface,. or into an atomizedliquid suspended As volatility controlling agents preferably may be usedone or more of the following types of substances; alcohols, such asethyl alcohol and the higher alcohols in fusel oil, water, cresols,phenol, aniline, crotonaldehyde, carbon tetrachloride, zinc chloride,aluminum chloride, sulphur dioxide, benzene numbered complex,nitro-benzene, etc. may be used at several the step of coalescing andprecipitating from the dispersion specific hydrocarbons. particularlythose in which has been induced a lower volatility by a volatilitycontrolling agent. Such hydrocarbons as are made to coalesce may do sodissolved in the volatility controlling agent or occluded by it. Moreparticularly. these steps are used in repeated alternate succession.

The features of the apparatus considered suitably adapted for carryingout th steps of dispersing and coalescing are embodied in means forgenerating vapors from the hydrocarbon mixture, means for passing liquidvolatility controlling agent into contact with the generated vapors atmultiple stages, with the general flow of the liquid agent and the vaporstreams being preferably countercurrent in direction, means forutilizing the velocity head energy of the vapors to disperse the liquidagent at each contact stage, and means for altering the velocity andpath of the stream containing dispersed hydrocarbons and agent in amanner which accelerate the intended coalescing and precipitation.

For clarity. the invention will be described by reference to adiagrammatic showing of a preferred form which the apparatus may take.In

Different solvents the drawings are represented two views of anapparatus.

Figure 1 shows an elevational view of tower I and appurtenances, acutaway section of the tower being shown to illustrate the internalstructure.

Figure 2 shows a horizontal cross sectional view of tower I at thesection indicated by line A-A in Figure l.

Figure 3 shows an elevational view of modified tower I in which arotating agitation is used to aid dispersion and centrifugal action instages.

Figure '4 shows a horizontal cross sectional view of modified tower byline 3-13 in Figure 3.

The tower I consists in a multiplicity of sections separated bysuperimposed plates 2, each plate being provided with vapor passagemeans 3 and 4, interconnecting the sections and liquid removal means,such as overflow pipes 5. Be-

tween each pair of successive plates a lateral spiral fluid passage isformed by stationary curved impingement vanes I, which are best viewedin a horizontal cross-section, as shown in Figure 3. These vanes may bebroadly described as sets of concentric and somewhat cylindrical tubespartitioning the fluid passages in each section and containing ports 9and I0, for making the passages continuous. th ports II), beingconstricted and provided with orifice inlets from adjoining liquidoverflow pipes to act as atomizers. At the upper end, tower is equippedwith a vapor outlet pipe 6, leading to any type of conventional vaporcondensing, collecting, or further fractionating means, and a fluidinlet pipe 8, for feeding fluid charging stock. At the extreme base ofthe tower are drain outlets II and I2, the former for any residuumcollected in the settling zone I3, of the tower I, and the latter fordecanting cleaner residuum from out. used to control flow in either orboth drain outlets. Betweenthe bottom plate 2, and the residuum settlingzone at base of the tower are a tangentially injecting inlet pipe 8, forthe charging stock, a perforated retaining pan I5, for retainstages;secondly, there is I at the section indicated which sludge is settled. Aliquid level control means I4. may be ing liquids in a rotary motioncaused by the tangential injection of charging stock and a vapor inletjet I6, located so as to contact the jetted vapors with liquids whichdrip from the pan I5. The ban and tangential injection arrangement isparticularly useful when the injected hydrocarbons are partly in liquidstate. for it acts to retain the liquids for a period to permitincreased vaporization, the vapor jet underneath acting further to stripthe residual portions which. drip from the pan. Condensed liquids whichcollect on the plates may be removed at any or all of the several stagesby withdrawal lines II, which can be two or more.

portion being returned through line I9, if desired, or, if of relativelylow or intermediate volatility, it may be withdrawn as a bottom productby line 20, or as a side-draw product by line 2I, the liquid hydrocarbonconcentrate being removed in an alternate manner, depending in turn onits relative volatility. Overhead from the auxiliary stripping columnmay be passed by pipe I9. into an intermediate part of tower I, or bypipe 22, to a condenser and receiver or other separating means (notshown). A reflux from the overhead of tower I, may be returned theretofor regulating conditions in the tower by pipe line 23. By means of,inlet lines 25, additional volatilizing fluids such a steam, gaseoushydrocarbons etc., and/or volatility controlling agents may be injectedat suitable temperatures into the spiralling stream of fluids toincrease the stream velocity and control the volatilities of thesubstances dispersed in the stream while permitting a desired amount ofcondensation at each stage in the tower.

In Figure 3, the modified tower 1 illustrates the same generalarrangement as shown in Figure 1, except that the corresponding tower inFigure 3 has provisions for mechanically rotated impingement vanes 26,in place of stationary vanes I, disposed in some sections between pairsof plates 2. The rotating vanes 28 are attached to a rotating shaft 21,which passes vertically through the central axis of tow'er I. The vanes26, may be two or more in number and are preferably designed asillustrated in Figure 4.

to add velocity to the vapor stream in place of liquids out of the vaporstream. "Shaft 21, ro-

tates in journals 28, and sockets 29, and protrudes through a packedfitting 30, in th base to a means for rotating said shaft such as forexample a driven gear Si, or by any other suitable manner. in pan I5,may be produced by vanes 32, attached to shaft 21, and rotatedtherewith.

As an illustration of a method for operation in which cyclichydrocarbons andasphaltic substances are to be segregated as a liquidconcentrate from more desirable parafflnic lubricating constituents in amixture containing those types f compounds the following example isgiven:

An initial charging stock e. g. a naphthene base bright stock, at atemperature of about 450 to 650 F., is led into the tower I, by inlet 8,in admixture with about an equal or larger proportion of crescls andsubjected to vaporization in tower I, at a pressure maintainedsufficiently plates Additional circulatory turbulence 2,280,!8 .low toobtain vaporization oi a substantial part of th hydrocarbons and thecresols at a pressure of about 200 to 700 mm. mercury absolute.

-A small proportion of gaseous hydrocarbons,

ponents of the-mixture, due to their higher inertia and lower fugacity,are precipitated out against the walls of the inpingement vanes andcollected as a liquid layer above each plate. One portion of the liquidlayers passes down through the overflow pipes 5, from which thedown-flowing liquid is aspirated by a constricted high -velocity fluidstream at points i and becomes thereby redispersed. Another portion ofthe liquid layers is withdrawn from one or more plates by pipes W, as aliquid concentrate of denser hydrocarbons mixed with some of thec'resols and is removed to a cresol stripping zone i8, in which thecresols are yolatilized for example, by addition of a small amount ofsteam,

which is injected by pipe 25. Instead of cresols there may be similarlyemployed high boiling.

polar compounds with relatively higher amnity for cyclic hydrocarbonsand asphaltic substances than for parafiinic compounds. Such polarcompounds may be selected from the following group: nitroaniline.aniline, chlornitrobenzene, nitrobenzene. nitroanisole.tetrahydronaphthalene, benzyl alcohol, .triacetin, diacetin, and othersimilar agents having higher afinity for cyclic hydrocarbons than forparaflinic compounds.

As a further example, denser molecules are separated from crackednaphtha introduced near the bottom of tower i, by inlet pipe d, at atemperature in the range of 400 to 600 F., and mixed in their spiralpaths up through said tower with fusel oil alcohol vapors having atemperature of about 200 or higher injected by pipe 25, preferably inabout equal proportions by weight to the weight of the chargedhydrocarbons. A

. minor quantity of steam at a temperature of about 400 1 1, or higheris injected at'the jet discharge of inlet 85. The vapors nearing out let6 are maintained at a temperature of about 350 F., with the pressureinthe tower being substantially atmospheric or slightly varying below orabove atmospheric pressure depending upon the desired end point for theoverhead ractlon. The overhead vapors highly enriched in lighter andmore paraifinic hydrocarbons may be passed together with residual steamto a fractionating tower wherein they are'fractionated to procurerelativel heavy reflux before final condensation so that aportion ofsaid heavy reflux maybe recycled to the upper part of tower i, throughpipe 23. for control of the overhead vapors. Portions of the liquidaggregate collected on intermediate plates 2 and comprising mainly amixture of alcohols and hydrocarbons of cyclic branched or unsaturatedcharacter are withdrawn from the side of tower i, by means of pipes H,to side stripper IS, in which they are refractionated in the presence ofa small quantity of steam to cause the hydrocarbons and steam to passoverhead through pipe 22, to a condenser thence a separator in which aconcentrate of hydrocarbons separated out as a liquid layer from awater.

layer, said concentrate of hydrocarbons being rich in hydrocarbons ofcyclic branched or unsaturated character. Liquid bottoms withdrawn fromthe base of tower II, are largely composed of alcohols while side drawswhich may be removed from an intermediate plate by pipe 2!. fromstripper II, are composed largely of alcohol and hydrocarbons which maybe further fractionated to further separate hydrocarbons fromalcohol asdescribed with respect to the stripping action in stripper [8.

Among some of the advantages which may be ascribed to the novel methodand apparatus of this invention are:

1. Economic construction of an eflicient fractionating means forsegregating specific components from a mixture of hydrocarbons, withelimination of several defects commonly found in packedtowers or bubbletowers by:-

(0) Having a low pressure drop (b) Avoiding channeling (c) Avoidingflooding (d) Having less liquid holdup (f) Having less dead spaces and(g) Imposing closer to equilibrium conditions mateticularly the heavierparticles out of the vapor stream.

It is to be understood that the apparatus may be equipp d with suitableindicating or recording devices for observation of pressures,temperatures, flow, etc., and that the apparatus is insulated wheredesired to maintain heat, and with valves-and pumps to regulate flow asrequired. The invention is not to be limited to' the particular form ofapparatus herein described nor by any specific example or theory usedfor the purpose of illustration.

Having described my invention, what I claim and desire to secure byLetters Patent, is as follows.

1. The method for-segregating a liquid concentrate. of specifichydrocarbons from a mixture of hydrocarbons, which comprises dispersing-into a. vapor stream the mixed hydrocarbons in the form of liquidparticles together with a volatility controlling compound having greaterchemical attraction for the specific hydrocarbons, to be segregated,said vapor stream flowing upwardly and through a series of spiralpassages, and coalescing said specific hydrocarbons together withvolatility controlling agent by centrifugal action on said vapor streamcarrying concurrently suspended therein the dispersed liquid particles.

2. The method for segregating a liquid concentrate of specifichydrocarbons of non-parafflnoid properties from a mixture ofhydrocarbons, which comprises partially vaporizing said mixturedispersinginto a vapor stream liquid particles of an unvaporized portionof the mixed hydrocarbons together with a volatility controllingcompound having greater chemical attrac (0) Being smaller in size for agiven capacity tion for the non-paramnoid hydrocarbons to be segregated,centrifuging the dispersion to coalesce non-par'afdnoid hydrocarbons andassociated volatility controlling compound in liquid pools over whichthe vapor stream is spirally passed, and withdrawing the non-coalesceddis persed hydrocarbonsoi paraihnoid character in vapor phase.

3. The method for segregating a liquid concentrate of specifichydrocarbons having relatively higher density from a mixture ofhydrocarbons containing hydrocarbons of lower density, which comprisesdispersing into a vapor stream discrete liquid particles of said mixtureof hydrocarbons with partial vaporization of the hydrocarbons inadmixture with a non-hydrocarbon organic compound having greateraflinity for the denser hydrocarbons of said mixture, and coalescingdenser hydrocarbons together with non-hydrocarbon organic compound thusdispersed into liquid pools by imposing centrifugal forces upon thedispersion in a spiral flow.

4. The method recited in claim 3, in which a substituted cyclichydrocarbon is used as the nonhydrocarbon organic compound and thespecific hydrocarbons of relatively higher density are cyclichydrocarbons.

5. The method recited in claim 3, in which an alcohol is used as thenon-hydrocarbon organic compound and the hydrocarbons of lower densityare straight chain paramns.

6. The method recited in claim 3, in which aniline is used as thenon-hydrocarbon organic compound.

'7. The method for segregating a liquid concentrate of specifichydrocarbons having relatively higher density from a mixture ofhydrocarbons containing hydrocarbons of lower density, which comprisespartiallyvaporizing a substantial portion of the hydrocarbon mixture,leading the vapors through a series of spiral passages guided by animpingement surface against which denser particles are forced out bycentrifugal action and caused to coalesce into a series of liquidaggregates of varying densities, redispersing portions of said liquidaggregates into said spiralling vapor stream, and withdrawing otherportions of said liquid aggregates as liquid concentrates of thespecific hydrocarbons having relatively higher densities, and separatingvaporized hydrocarbons of lower density.

8. The method for segregating a liquid concentrate of specifichydrocarbons having relatively higher densities from a mixture ofhydrocarbons containing hydrocarbons of lower density, which comprisesvaporizing a substantial portion of the hydrocarbon mixture, leading thevapors through a series of spiral passages guided by an impingementsurface against which liquid particles are forced out by centrifugalaction imparted to the vapor stream and caused to coalesce into a seriesof liquid pools, redispersing portions of said liquid pools into saidspiraling vapor stream as discrete liquid particles together with avolatility controlling compound having greater chemical attraction forthe specific hydrocarbons to be segregated,

withdrawing portions of said liquid pools as liquid concentrates of thespecific hydrocarbons having relatively higher densities, and separat-ving vaporized hydrocarbon of lower density.

ERNEST A. OCC N.

